A soft tape, a mirror and thirty seconds are enough — if you place the tape in the right spot.
Find the natural waist
The natural waist is the narrowest point of the torso, generally a couple of centimetres above the navel. Bend sideways: the crease that forms marks it. Trouser waistbands often sit lower, so measure both if you are buying jeans.
Tape placement
Stand relaxed with feet together and breathe out normally. Wrap the tape horizontally, parallel to the floor, snug enough to stay put but not compressing the skin. Check the back in a mirror; a tape that rides up behind you inflates the reading.
Record and repeat
Take the measurement twice and use the average. Measure at the same time of day for consistency, as waist readings vary slightly after meals. Note whether you measured over bare skin or a thin layer.
Turn it into a size
Enter the measurement into a waist converter to see the US, UK, EU and international equivalents. Compare that against the retailer's chart, and remember that low-rise garments are drafted for a hip measurement rather than the natural waist.
Frequently Asked Questions
Should I measure over clothes?
Bare skin or a thin base layer gives the most repeatable number. Bulky fabric can add two or more centimetres.
Inches or centimetres?
Either works. Centimetres give finer resolution, which helps when you fall between two sizes.